Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter (Beilstein Journal of Organic Chemistry)

Abstract The intramolecular cyclization of a C-3-tetrasubstituted furanoid sugar amino acid-derived linear tetrapeptide afforded an oxazolone pseudo-peptide with the formation of an oxazole ring at the C-terminus. A conformational study of the oxazolone pseudo-peptide showed intramolecular C=O···HN(II) hydrogen bonding in a seven-membered ring leading to a γ-turn conformation. This fact was supported by a solution-state NMR and molecular modeling studies. The oxazolone pseudotetrapeptide was found to be a better Cl−-selective transporter for which an anion–anion antiport mechanism was established. Beilstein J. Org. Chem. 2019, 15, 2419–2427. doi:10.3762/bjoc.15.234